Once again, I don't understand the hint. After 22 moves, I got stuck and asked for a hint. It was 7 in C4R2. I had candidates of 2, 3 and 7 in that cell. Do the 2 and 3 some drop out? My other 7 in C4 is in C4R8, but I can't see any way to get rid of it. There must be something that I am missing.